The Longest Known Frozen Human Embryo
December 20, 2017The Longest Known Frozen Human Embryo to Result in a Successful Birth
How much do you know about frozen embryos?
Frozen embryos are microscopic and virtually take up no space. Plastic tubes known as “straws” carry these little embryos. A small straw can hold up to three embryos. Each tube is attached with a rod of a certain color and a name on it. Special printers are used to print identification codes on labels to keep careful track of each embryo. Families are grouped together in these frozen containers, each with their own combination of colors and codes.
Embryos can be frozen during several stages of development: from the day of fertilization, when they are only a cell, to five or six days later in the blastocyst stage, when they are the same size but are comprised of more cells. During the first seven days alive, they grow within the external membrane of the oocyte, exactly like a chick in an eggshell. The moment in which the cells break the membrane is known as the hatching of the blastocyst. They come out and immediately implant themselves in the inner layer of the uterus. They can be frozen up until that moment.
The procedure for extracting these embryos usually lasts a couple of hours. They are put to swim in a cryoprotectant solution that prevents ice crystals from forming where they are softly picked and drawn into the straws. These straws are placed in a freezing machine that slowly decreases the temperature to reach -196 degrees Celsius in 90 minutes. Finally, these straws are placed in a container filled with liquid nitrogen.
The first baby born from this system came to life 30 years ago.
Currently, embryologists prefer to use another similar system known as vitrification. The difference is the change in temperature. The process of freezing the embryo from 37 degrees to -197 degrees Celsius only lasts a few minutes instead of 90 minutes. The result is a solid material similar to glass.
On October 14th, 1992, a human embryo was frozen and put in storage for possible later birth. On March 13th, Carol Sommerfelt, an Embryology Lab Director at the National Embryo Donation Center, thawed the embryo. On November 25th, Emma Wren Gibson was delivered by Dr. Jeffery Kennan, a Medical Director at the NEDC.
This baby had a 75% chance of having their embryo thaw correctly and a 25% chance of implanting on the mother’s uterus. This is a world record for the longest term from a frozen embryo to the birth of the baby. Congratulations to the parents, Soma hopes you have a lifetime of happiness and good health.